Quote:

LSD is a synthetic compound. It is derived from Iysergic acid which is found in Hawaiian Woodrose and Morning Glory seeds, or Ergot fungus, which can grow on rye, wheat, and other grams. Lysergic acid is also psychoactive, although not nearly as potent as LSD, and has been consumed for millennia in the form of the above mentioned plant sources. The most common street name for LSD is "acid."

Read the Complete version here...
http://www.erowid.org/library/books_online/essential_psychedelic_guide/lsd.shtml